Valves are often used in process control plants or systems to control the flow of process fluids. One common type of valve used in severe service applications (e.g., high pressure applications, high temperature applications, etc.), is a flow down angle-style control valve. Angle-style control valves are typically used in the chemical and petroleum industries, which often require control of residual oils or other liquids with coking properties.
Angle-style control valves include a body having an inlet turned at an angle from an outlet. A flow control member (e.g., a plug) is disposed within a passageway between the inlet and outlet and is operatively coupled to a valve stem. An actuator (e.g., a pneumatic actuator, an electric actuator, a hydraulic actuator, etc.) is operatively coupled to the valve stem (e.g., a sliding stem) to drive the flow control member between an open position and a closed position to control the flow of fluid through the valve. In the closed position, the flow control member engages a circumferential seal or seat ring disposed between the inlet and the outlet of the valve. A seat ring retainer or liner retains the seat ring within the valve body and has an elongated body that protects a surface of the outlet port of the valve body from, for example, corrosion, etc.
Due to the angle of the valve body, angle-style valves advantageously allow for easy draining, because the valve body or flow path of such valves does not have any pockets or areas that allow accumulation of fluid and/or residue. Furthermore, due to the angle of the valve body, angle-style valves advantageously channel fluid forces toward the center of the fluid flow, thereby channeling fluid forces such as, for example, imploding bubbles formed due to cavitation away from the valve body and/or the valve trim (e.g., seat ring, cage, valve plug, etc.). Channeling the fluid forces toward the center of the valve body prevents or substantially reduces damage to the valve trim and/or the valve body.
In high differential pressure applications, for example, fluid (e.g., a liquid, gas, steam, etc.) at an inlet of a valve typically has a relatively high pressure that is reduced to a substantially lower pressure at an outlet of the valve. The relatively high pressure differential can cause cavitation, flashing, vibration, and/or other unwanted fluid forces or effects between the inlet and the outlet of the valve. Due to the angle between the inlet and the outlet of the angle-style valve, the fluid forces caused by the pressure differential are channeled toward the center of the outlet and/or downstream piping. However, the pressure differential between the inlet and the outlet increases the velocity of the fluid flowing through the valve body. The increased velocity can cause the fluid flowing through the valve to experience turbulent flow, which can impart vibration to the valve body and/or downstream piping. Vibration can cause the seat retainer ring or liner to become loose and/or dislodge from the valve body, thereby resulting in lost production for the time required to disassemble the valve and re-couple the liner to the valve body.